This invention relates to textile manufacturing and treating processes comprising hydrophobically modified polymers. The polymers are especially useful in preventing the backstaining of denim during a stonewashing process.
The production of xe2x80x9cagedxe2x80x9d denim garments is obtained by nonhomogeneous removal of indigo dye trapped inside the fibers by the cooperative action of cellulase enzymes and mechanical factors such as beating and friction. However, when cellulases are present, the removed indigo backstains the reverse side of the fabric which is undesirable.
WO 9325655 describes enzymatic compositions for stonewashing. Indigo backstaining which occurs in the presence of cellulase enzymes is described in an article entitled, xe2x80x9cIndigo Backstaining During Cellulase Washingxe2x80x9d Cavaco-Paulo et al., Textile Res. J. 68(6), 398-401 (1998).
Conventional anti-dye transfer polymers such as polyvinylpyrrolidone and polyvinylpyrridine-N-oxide are effective for preventing the redeposition of direct dyes that are typically used on cotton. However, such conventional anti-dye transfer polymers are not effective in preventing the backstaining of indigo dyes due to the extreme hydrophobicity of indigo dyes.
Discoloration is also a problem in textile bleaching processes wherein heavy metal ions and salts are present. For example, bleaching by hydrogen peroxide is generally carried out under an alkaline condition of a pH value of 10 to 14, and the reaction effectively improving the whiteness is represented by the formula: H2O2xe2x86x92HOxe2x88x922+H+, the active bleaching component is the perhydroxyl ion. However, under alkaline conditions (pH of at least 10), the side reaction represented by the formula: 2H2O2xe2x86x922H2O+O2 is promoted by heavy metal ions which are contained in cellulose fibers of cotton, flax or the like, and in a bleaching bath, such as iron, calcium, copper and manganese, and therefore, discoloration of the fibers occurs, and the fibers are made brittle.
To eliminate this disadvantage, sodium silicate is frequently used as a bleach stabilizer, but the use of sodium silicate is disadvantageous in that water-insoluble salts of calcium and magnesium, i.e., silicate scales, are formed, and these insoluble salts adhere to and are deposited on a bleached textile and a bleaching apparatus to cause a silicate scale problem.
Bleach stabilizers other than sodium silicate include polyphosphoric acid salts such as sodium tripolyphosphate, and aminocarboxylate organic chelating agents such as ethylenediamine-tetraacetic acid (EDTA) and diethylenetriamine-pentaacetic acid (DTPA). These bleach stabilizers do not cause a silicate scale problem, however, at a pH of 10 to 14, the chelating capacity is reduced. Moreover, these bleach stabilizers are insolubile in the presence of an excessive amounts of hardness ions.
Heavy metal ions also cause problems in the desizing, scouring, mercerising, and dyeing processes of textiles by forming insoluble salts. The insoluble salts deposit on textiles and equipment causing scale problems and blemishes on textiles.
The present invention provides a textile manufacturing or treating process comprising treating a textile with a solution or dispersion of a hydrophobically modified polymer having a hydrophilic backbone and at least one hydrophobic moiety,
wherein said hydrophilic backbone is prepared from at least one monomer selected from the group consisting of ethylenically unsaturated hydrophilic monomer selected from the group consisting of unsaturated C1-C6 acid, amide, ether, alcohol, aldehyde, anhydride, ketone and ester; polymerizable hydrophilic cyclic monomer; non-ethylenically unsaturated polymerizable hydrophilic monomer which is selected from the group consisting of glycerol and other polyhydric alcohols; and combinations thereof,
wherein said hydrophilic backbone is optionally substituted with one or more amino, amine, amide, sulfonate, sulfate, phosphonate, hydroxy, carboxyl or oxide groups;
wherein said hydrophobic moiety is prepared from at least one hydrophobic monomer or a chain transfer agent, said hydrophobic monomer is selected from the group consisting of a siloxane, saturated or unsaturated alkyl and hydrophobic alkoxygroup, aryl and aryl-alkyl group, alkyl sulfonate, aryl sulfonate, and combinations thereof, and said chain transfer agent has 1 to 24 carbon atoms and is selected from the group consisting of a mercaptan, amine, alcohol, and combinations thereof,
wherein said hydrophobically modified polymer is present in an amount of from 0.001 to 50 weight percent, based on the total weight of the solution or dispersion.
According to another aspect, the invention provides a method to prevent the backstaining of denim during a stonewashing process comprising adding 0.001 to 50 weight percent, based on the total weight of the solution or dispersion, of a solution or dispersion of the hydrophobically modified polymer.
The hydrophobically modified polymers prevent redeposition of indigo onto denim in a stonewashing process, help stabilize hydrogen peroxide in a bleaching process, reduce scale and prevents deposition of heavy metal ions such as iron, calcium and magnesium in a scouring, desizing, and mercerising process, and disperse direct and disperse dyes, and suspend unfixed dyes in order to provide a consistent and level dyeing of textiles in a dyeing process.
An additional advantage is that the hydrophobically modified polymers complex salts, such as calcium, magnesium and iron salts, during the dyeing process which prevents the salts from depositing on the textiles and causing blemishes, or precipitating the dyes out of solution which reduces the efficiency of the dyes. The hydrophobically modified polymers also suspend polyester trimers during the dyeing of polyester.
The invention provides a textile manufacturing or treating process comprising a solution or dispersion of a hydrophobically modified polymer. Such textile manufacturing and treating processes include stonewashing of denim, desizing, scouring, mercerising, bleaching, and dyeing processes. As used herein, these terms have the following meanings:
(1) xe2x80x9cStonewashingxe2x80x9d refers to the production of xe2x80x9cagedxe2x80x9d denim garments with cellulase enzymes in the presence of mechanical factors such as beating and friction.
(2) xe2x80x9cDesizingxe2x80x9d is essentially a part of the scouring process, and rapid removal of size is important especially in continuous preparation processes. Desizing of sized fabrics is commonly carried out using water washing at varying temperatures or with enzymes. Desizing can also be carried out effectively with alkaline, preferably caustic solutions, and those alkaline solutions can be very dilute.
(3) xe2x80x9cScouringxe2x80x9d involves removing or reducing the level of fats, waxes, oils, dirt, and so forth on a textile. Apart from the aesthetic benefits of clean fabric, the major reason for scouring is to improve the extent and uniformity of absorbency for subsequent processes, especially dyeing. Scouring generally takes place using mild alkalinity and surfactants as wetting agents, such as alkylbenzenesulfonate and alkylphenol ethoxylates. It is noted that scouring is particularly important with natural fibers which contain much more extraneous matter than synthetic fibers. For example, cotton, requires high alkalinity scouring, which swells the fibers, allowing access to the lumen and removing soil from the surface.
(4) xe2x80x9cBleachingxe2x80x9d involves bleaching of the various types of textiles with a peroxide bleaching compound. Suitable peroxide compounds are water soluble peroxides, particularly alkali metal peroxides, preferably sodium peroxide, and hydrogen peroxide, the latter being particularly preferred. The peroxide bleaching is carried out in an alkaline medium. To achieve the alkaline conditions, it is advantageous to use an alkali metal hydroxide, preferably potassium or sodium hydroxide.
(5) xe2x80x9cMercerisingxe2x80x9d is used to swell cotton fibers in order to increase their lustre, strength, and dyeability. Generally, a cold solution of sodium hydroxide is used; however, hot mercerising techniques and the use of acids, such as cresylic acid along with a cosolvent, may also be employed.
(6) xe2x80x9cDyeingxe2x80x9d involves the application of a solution or a dispersion of a dye to a textile followed by some type of fixation process. The dye solution or dispersion is almost always an aqueous medium, and a major objective of the fixation step is to ensure that the colored textile exhibits satisfactory fastness to subsequent treatment in aqueous wash liquors.
Suitable textiles to be treated with the hydrophobically modified polymer of the invention are, for example, cotton, denim, polyacrylics, polyamides, polyesters, polyolefins, rayons, wool, linen, jute, ramie, hemp, sisal, regenerated cellulosic fibers such as rayon or cellulose acetate, leather, and combinations thereof. The textiles can be in a variety of forms, for example, yarn, tops, woven, knitted, plush, carpets, and finished garments.
The concentration of the hydrophobically modified polymer in a textile manufacturing or treating process is preferably from about 0.001 to about 50 weight percent, based on the weight of the solution or dispersion containing the hydrophobically modified polymer which is used in the textile process. More preferably, the hydrophobically modified polymer is present in an amount of from 0. 1 to 25 weight percent, most preferably from 1 to 10 weight percent.
The hydrophobically modified polymer has a hydrophilic backbone and at least one hydrophobic moiety. The hydrophilic backbone may be linear or branched and is prepared from at least one ethylenically unsaturated hydrophilic monomer selected from unsaturated acids preferably C1-C6 acids, amides, ethers, alcohols, aldehydes, anhydrides, ketones and esters; polymerizable hydrophilic cyclic monomers; and non-ethylenically unsaturated polymerizable hydrophilic monomers selected from glycerol and other polyhydric alcohols. Combinations of hydrophilic monomers may also be used. Preferably the hydrophilic monomers are sufficiently water soluble to form at least a 1% by weight solution in water.
Preferably the ethylenically unsaturated hydrophilic monomers are mono-unsaturated. Examples of ethylenically unsaturated hydrophilic monomers are, for example, acrylic acid, methacrylic acid, ethacrylic acid, alpha-chloro-acrylic acid, alpha-cyano acrylic acid, beta methyl-acrylic acid (crotonic acid), alpha-phenyl acrylic acid, beta-acryloxy propionic acid, sorbic acid, alpha-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, beta-styryl acrylic acid (1-CARBOXY4-phenyl butadiene-1,3), itaconic acid, maleic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, fumaric acid, tricarboxy ethylene, 2-acryloxypropionic acid, 2-acrylamido-2-methyl propane sulfonic acid, vinyl sulfonic acid, vinyl phosphonic acid, 2-hydroxy ethyl acrylate, tri methyl propane triacrylate, sodium methallyl sulfonate, sulfonated styrene, allyloxybenzenesulfonic acid, dimethylacrylamide, dimethylaminopropylmethacrylate, diethylaminopropylmethacrylate, vinyl formamide, vinyl acetamide, polyethylene glycol esters of acrylic acid and methacrylic acid and itaconic acid, vinyl pyrrolidone, vinyl imidazole, maleic acid, and maleic anhydride. Combinations of ethylenically unsaturated hydrophilic monomers may also be used. Preferably, the ethylenically unsaturated hydrophilic monomer is selected from acrylic acid, maleic acid, and itaconic acid.
The polymerizable hydrophilic cyclic monomers may have cyclic units that are either unsaturated or contain groups capable of forming inter-monomer linkages. In linking such cyclic monomers, the ring-structure of the monomers may either be kept intact, or the ring structure may be disrupted to form the backbone structure. Examples of cyclic units are sugar units such as saccharides and glucosides, cellulose ethers, and alkoxy units such as ethylene oxide and propylene oxide.
The hydrophilic backbone of the hydrophobically modified polymer may optionally be substituted with one or more amino, amine, amide, sulfonate, sulfate, phosphonate, hydroxy, carboxyl or oxide groups. The hydrophilic backbone of the polymer may also contain small amounts of relatively hydrophobic units, for example, units derived from polymers having a solubility of less than 1 g/l in water, provided that the overall solubility of the polymer in water at ambient temperature and at a pH of 3.0 to 12.5 is more than 1 g/l, more preferably more than 5 g/l, and most preferably more than 10 g/l. Examples of relatively water insoluble monomers are vinyl acetate, methyl methacrylate, ethyl acrylate, ethylene, propylene, hydroxy propyl acetate, styrene, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, behenyl methacrylate.
The hydrophobic moieties are linked to the hydrophilic backbone by any possible chemical link, although the following types of linkages are preferred: 
Preferably the hydrophobic moieties are part of a monomer unit which is incorporated in the polymer by copolymerising hydrophobic monomers and the hydrophilic monomers making up the backbone of the polymer. The hydrophobic moieties preferably include those which when isolated from their linkage are relatively water insoluble, i.e. preferably less than 1 g/l more preferred less than 0.5 g/l, most preferred less than 0.1 g/l of the hydrophobic monomers, will dissolve in water at ambient temperature and a pH of 3 to 12.5.
Preferably the hydrophobic moieties are selected from siloxanes, aryl sulfonate, saturated and unsaturated alkyl moieties optionally having sulfonate end groups, wherein the alkyl moieties have from 5 to 24 carbon atoms, preferably from 6 to 18, most preferred from 8 to 16 carbon atoms, and are optionally bonded to the hydrophilic backbone by means of an alkoxylene or polyalkoxylene linkage, for example a polyethoxy, polypropoxy or butyloxy (or mixtures of same) linkage having from 1 to 50 alkoxylene groups. Alternatively the hydrophobic moiety may be composed of relatively hydrophobic alkoxy groups, for example butylene oxide and/or propylene oxide, in the absence of alkyl or alkenyl groups.
Examples of hydrophobic monomers include styrene, xcex1-methyl styrene, 2-ethylhexyl acrylate, octylacrylate, lauryl acrylate, stearyl acrylate, behenyl acrylate, 2-ethylhexyl methacrylate, octylmethacrylate, lauryl methacrylate, stearyl methacrylate, behenyl methacrylate, 2-ethylhexyl acrylamide, octylacrylamide, lauryl acrylamide, stearyl acrylamide, behenyl acrylamide, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 1-vinyl naphthalene, 2-vinyl naphthalene, 3-methyl styrene, 4-propyl styrene, t-butyl styrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzyl styrene, and 4-(phenylbutyl) styrene. Combinations of hydrophobic monomers may also be used.
Alternatively, the hydrophobic moiety may be introduced into the polymer in the form of a chain transfer agent. The chain transfer agent has from 1 to 24 carbon atoms, preferably 1 to 14 carbon atoms, more preferably 3 to 12 carbon atoms. The chain transfer agent is selected from mercaptans or thiols, amines and alcohols. A combination of chain transfer agents can also be used. Mercaptans useful in this invention are organic mercaptans which contain at least one xe2x80x94SH or thiol group and which are classified as aliphatic, cycloaliphatic, or aromatic mercaptans. The mercaptans can contain other substituents in addition to hydrocarbon groups, such substituents including carboxylic acid groups, hydroxyl groups, ether groups, ester groups, sulfide groups, amine groups and amide groups. Suitable mercaptans are, for example, methyl mercaptan, ethyl mercaptan, butyl mercaptan, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptoacetic acid, mercaptopropionic acid, thiomalic acid, benzyl mercaptan, phenyl mercaptan, cyclohexyl mercaptan, 1-thioglycerol, 2.2xe2x80x2-dimercaptodiethyl ether, 2,2xe2x80x2-dimercaptodipropyl ether, 2,2xe2x80x2-dimercaptodiisopropyl ether, 3,3xe2x80x2-dimercaptodipropyl ether, 2,2xe2x80x2-dimercaptodiethyl sulfide, 3,3xe2x80x2-dimercaptodipropyl sulfide, bis(beta-mercaptoethoxy) methane, bis(beta-mercaptoethylthio)methane ethanedithio-1,2, propanedithiol-1,2, butanedithiol-1,4,3,4-dimercaptobutanol-1, trimethylolethane tri(3-mercaptopropionate), pentaerythritol tetra(3-mercapto-propionate), trimethylolpropane trithioglycolate, pentaerythritol tetrathio-glycolate, octanethiol, decanethiol, dodecanethiol, and octadecylthiol. Preferred mercaptan chain transfer agents include 3-mercaptopropionic acid and dodecanethiol.
Suitable amines which are useful as chain transfer agents are, for example, methylamine, ethylamine, isopropylamine, n-butylamine, n-propylamine, iso-butylamine, t-butylamine, pentylamine, hexylamine, benzylamine, octylamine, decylamine, dodecylamine, and octadecylamine. A preferred amine chain transfer agent is isopropyl amine and docylamine.
Suitable alcohols which are useful as chain transfer agents are, for example, methanol, ethanol, isopropanol, n-butanol, n-propanol, iso-butanol, t-butanol, pentanol, hexanol, benzyl alcohol, octanol, decanol, dodecanol, and octadecanol. A preferred alcohol chain transfer agent is isopropanol and dodecanol.
The hydrophobically modified polymers are prepared by processes known in the art such as disclosed in U.S. Pat. No. 5,147,576. Preferably, the hydrophobically modified polymers are prepared using conventional aqueous polymerization procedures, but employing a process wherein the polymerization is carried out in the presence of a suitable cosolvent and wherein the ratio of water to cosolvent is carefully monitored so as to maintain the ratio of water to cosolvent to keep the polymer, as it forms, in a sufficiently mobile condition and to prevent unwanted homopolymerization of the hydrophobic monomer and subsequent undesired precipitation thereof.
In one embodiment, the hydrophobically modified polymer has Structure (I): 
wherein z is 1; (x+y): z is from 0.1:1 to 1,000:1, preferably from 1:1 to 250:1; in which the monomer units may be in random order; y is from 0 to a maximum equal to the value of x; and n is at least 1; R1 is selected from the group consisting of xe2x80x94COxe2x80x94Oxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Oxe2x80x94COxe2x80x94, xe2x80x94CH2xe2x80x94, xe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94CH2xe2x80x94Oxe2x80x94, and xe2x80x94CH2xe2x80x94Oxe2x80x94COxe2x80x94, or is absent; R2 is from 1 to 50 independently selected alkyleneoxy groups, preferably ethylene oxide or propylene oxide groups, or is absent, provided that when R3 is absent and R4 is H or contains no more than 4 carbon atoms, then R2 is an alkyleneoxy group with at least 3 carbon atoms; R3 is a phenylene linkage, or is absent; R4 is selected from the group consisting of H, C1-C24 alkyl, C1-C24 alkyl sulfonate, and C2-C24 alkenyl group, provided that a) when R1 is xe2x80x94Oxe2x80x94COxe2x80x94 or xe2x80x94COxe2x80x94Oxe2x80x94 or xe2x80x94COxe2x80x94NHxe2x80x94, R2 and R3 are absent and R4 has at least 5 carbon atoms; b) when R2 is absent, R4 is not H and when R3 is absent, then R4 has at least 5 carbon atoms; R5 is H or xe2x80x94COOA4; R6 is H or a C1-C4 alkyl; and A1, A2, A3, and A4 are independently selected from the group consisting of H, alkali metals, alkaline earth metals, ammonium bases, amine bases, C1-C4 alkyl, and (C2H4O)t H, wherein t is from 1-50.
In one embodiment, the hydrophobically modified polymer has Structure (II): 
wherein Q2 has the Structure (IIa): 
wherein Q1 is a multifunctional monomer, allowing the branching of the polymer, wherein the monomers of the polymer may be connected to Q1 in any direction or order, therewith possibly resulting in a branched polymer, preferably Q1 is selected from trimethyl propane triacrylate (TMPTA), methylene bisacrylamide or divinyl glycol; r is 1; and (x+y+p+q+r):z is from 0.1:1 to 1,000:1, preferably from 1:1 to 250:1; in which the monomer units may be in random order; and preferably either p and q are zero, or r is zero; R7 and R8 are independently xe2x80x94CH3 or xe2x80x94H; R9 and R10 are independently substituent groups selected from the group consisting of amino, amine, amide, sulfonate, sulfate, phosphonate, phosphate, hydroxy, carboxyl and oxide groups, preferably xe2x80x94SO3Na, xe2x80x94COxe2x80x94Oxe2x80x94C2H4xe2x80x94OSO3Na, xe2x80x94COxe2x80x94Oxe2x80x94NHxe2x80x94C(CH3)2xe2x80x94SO3Na, xe2x80x94COxe2x80x94NH2, xe2x80x94Oxe2x80x94COxe2x80x94CH3, and xe2x80x94OH.
In one embodiment, the hydrophobically modified polymer has Structure 
(III):
wherein z=1; x:z is from 0.1:1 to 1,000:1, preferably from 1:1 to 250:1; n is 1; A1 may be a branching point wherein other molecules of Structure (III) are attached.
Examples of molecules having Structure (III) are hydrophobically modified polyglycerol ethers or hydrophobically modified condensation polymers of polyglycerol and citric acid anhydride.
In one embodiment, the hydrophobically modified polymer has Structure (IV): 
wherein (x+y):z is from 0.1:1 to 1,000:1, preferably from 1:1 to 250:1; wherein the monomer units may be in random order; R11 is selected from the group consisting of xe2x80x94OH, xe2x80x94NHxe2x80x94COxe2x80x94CH3, xe2x80x94SO3A1 and xe2x80x94OSO3A1; R12 is selected from the group consisting of xe2x80x94OH, xe2x80x94CH2OH, xe2x80x94CH2OSO3A1, COOA1, and xe2x80x94CH2xe2x80x94OCH3.
Examples of molecules having Structure (IV) are hydrophobically modified polydextran, -dextran sulfonates, -dextran sulfates and lipoheteropolysaccharides.
In one embodiment, the hydrophobically modified polymer has Structure (V): 
wherein z, n and R1-R6 are as defined above for Structure (I); and x is as defined for Structure (III).
In one embodiment, the hydrophobically modified polymers are hydrophobically modified condensation polymers of -hydroxy acids. Examples of suitable polymer backbones are polytartronate, polycitrate, polyglyconate, and mixtures thereof. In another embodiment, the hydrophobically modified polymers are hydrophobically modified polyacetals.
It is within the scope of the invention that a sample of hydrophobically modified polymers may contain full salt polymers (A1-A4 all other than hydrogen), full acid polymers (A1-A4 all hydrogen) and part-salt polymers (one or more of A1-A4 hydrogen and one or more other than hydrogen).
The salts of the hydrophobically modified polymers may be formed with any organic or inorganic cation defined for A1-A4 and which is capable of forming a water-soluble salt with a low molecular weight carboxylic acid. Preferred are the alkali metal salts, especially of sodium or potassium.
In one embodiment, the hydrophobically modified polymer is used to prevent backstaining of denim during the stonewashing of denim articles. While not wishing to be bound by any particular theory, the present inventors believe that the hydrophobically modified polymer bind with indigo dye or indigo cellulase complex and prevents the indigo dye and/or indigo cellulase complex from redepositing onto the denim.
In one embodiment, where the hydrophobically modified polymer is used at the steps of desizing, scouring and bleaching textiles, not only a hydrogen peroxide-stabilized effect but also a high decomposition-promoting effect can be obtained, and an abnormal decomposition by metal ions such as iron, copper and calcium ions can be controlled. Furthermore, a good dispersibility is given to decomposition products, for example in the case of polyester the redeposition of polyester trimers has a deleterious effect on the overall dying, and thus, it is neceassary to use the hydrophobically modified polymers to suspend the trimers and keep them from redepositing on the fabric.
In one embodiment, where the hydrophobically modified polymer is used for the mercerization of cotton or flax, the hydrophobically modified polymer can be incorporated into a mercerizing bath or soaping bath of a yarn mercerizing machine or a knitted or woven fabric mercerizing machine. Since the alkali resistance of the hydrophobically modified polymer is good, a decomposition or separation of the hydrophobically modified polymer per se does not occur, the deposition of scales on a roll or the like is prevented, and the dispersibility of the bath is improved.
The hydrophobically modified polymer complexes heavy metal ions in the manufacturing or treating of textiles. For example, the hydrophobically modified polymers help stabilize hydrogen peroxide in the bleaching process, reduce scale and prevent deposition of heavy metal ions such as iron, calcium and magnesium during the scouring, desizing, mercerising, and bleaching processes. In addition, the hydrophobically modified polymers prevent redeposition of particulate soils onto the textiles.
Furthermore, in the dyeing process, the hydrophobically modified polymers disperse direct and dispersed dyes, and suspend unfixed dyes, and thus, provide a consistent and level dyeing of textiles. An additional advantage is that the hydrophobically modified polymers complex salts, such as calcium, magnesium and iron salts, during the dyeing process which prevents the salts from depositing on the textiles and causing blemishes, or precipitating the dyes out of solution which reduces the efficiency of the dyes.
The following nonlimiting examples illustrate further aspects of the invention.